This spell summons some sort of mutilated angel or goddess with her head and limbs missing. Does anybody know what she's supposed to be? A fallen angel perhaps?
The final spell for Soul Eater summons Grim Reapers (can't remember if they appear in the Suikoden 4 version) which makes sense because it is the true rune of death and the symbol is a Grim Reaper with a scythe. I just don't think I've seen an explanation for the entity that appears for the Everlasting Mercy spell. Sorry if it has been written down on this site and I've missed it.